Monobaths containing sodium polyacrylate and polyvinyl-pyrrolidone



United States Patent r 3,167,429 MONOBATHS CONTAINING SODXUM FQLYACRY- LATE AND PQLYVlNYL-PYRROLHDUNE Marilyn Levy, Red Bank, NJ, assignor to the United States of America as represented by the Secretary of the Army No Drawing. Filed May 26, 1961, Ser. No. 113,041 3 Claims. ((11. 96-61) (Granted under Title 35, US. Code (1952), see. 266) now abandoned, in which the applicant is coinventor with Willard C. Burner, a single step processing composition for photo-sensitive materials is presented. This bath produces excellent results and creates images having normal density values without excessive fog density and without decrease in fihn speed. In the present invention the advantages of such a bath are enlarged to apply to those special cases where the bath must have substantial viscosity to avoid spilling. For example, in airborne processing or in the operation of mobile ground processing laboratories. It has been found however when viscous monobaths are used to process photo-sensitive materials the silver that precipitates from the reaction of the monobath on exposed silver halide has a tendency to produce a cloudy veil that obscures the developed image. Such a condition is intolerable for critical applications. It so happens where processing equipment is subject to tipping and irregular displacement, as above suggested, the additional requirement for fast processing may also be present particularly in military operations wherein this additional requirement results from the urgency to view the finished picture as soon as possible. Fast processing also is urgent where the image must be immediately scanned for transmission to a remote point or to quickly supply data to data processing systems.

An effective manner for decreasing processing time is to increase the temperature of the bath. By so doing however the clouding tendency is increased. Heretofore ammonia salts have been added to the composition to correct this difiiculty in which case the silver is dissolved which clears the cloudy condition. However the ammonia decreases the activity of the developer ingredients in the monobath and increases the rate of fixation to the point where both speed and maximum density in the finished image are seriously reduced. In addition the ammonia fumes released produce a toxic atmosphere.

In the practice of the invention the above difiiculties are overcome. The formulation of the invention includes the developing and fixing elements of an eificient rapid acting low fogging monobath the ingredients of which are given in examples of the invention presented hereinafter. In addition to the developing and fixing ingredients a thickening agent is added such as sodium polyacrylate. More or less of this material is added depending upon the viscosity desired. To this composition is added a small quantity of polyvinylpyrrolidone. This bath is stable and can be used at temperatures up to 130 F. producing no cloudy silver precipitate.

An investigation of the mechanism producing this valuable result tends to show that the silver precipitate is kept in a transparent colloidal suspension by the polyvinylice pyrrolidone which acts as a protective colloid. The polyvinylpyrrolidone does not dissolve in the bath but remains in a suspension that is visible as microscopic droplets when viewed thru a microscope.

On the other hand, the monobath may have sufficient viscosity to be applied to the sensitive material in a thin layer by spreading it with a spatula or squeegee or by rolling it onto the emulsion. The latter technique may be carried out independently of any adverse positional environment. This high viscosity technique lends itself to a completely mechanized non-spilling processing system for rapid handling and processing of photographic materials.

The exposed sensitive material is maintained in contact with the monobath until the image is entirely cleared. At 130 F. the processing time may be 10 seconds depending on the film. The picture is then ready for immediate use. If desired subsequent washing and drying steps may be performed to prolong the initial characteristics of the image. V

The following examples of solutions embodying the invention have been found to produce high quality images free of excess fog density and clouding precipitate. Also the images so processed exhibit normal density values with no indication of reduced emulsion speed. i 1

Water to make 1 liter.

A quantity of chemically inactive thickening material.

Metol gm 10 Sodium sulphite (anhd.) gm 50 Hydroquinone gm 40 Potassium alum gm 2() Sodium hydroxide gm 35 Sodium thiosulphate gm 110 .5 solution of 6-nitrobenzimidazole nitrate cc 20 Polyvinylpyrrolidone gm 10 Example 7 Water to make 1 liter. A quantity of chemically inactive thickening material.

Sodium sulphite (anhd.) gm 6O 1-phenyl-3-pyrazolid-one gm." .8 Hydroquinone gm 30 Sodium thiosulphate gm to 250 Formaldehyde- (38% cc: l0 Ethylene diamine 77% cc 2 to 50 Polyvinylpyrrolidone gm 3 to 15 Example 8 Water to make 1 liter. A quantity of chemically inactive thickening material.

Sodium sulphite (anhd.) gm 50 Diaminophenol hydrochloride gm 15 Hydroquinone Q gm 5 Glycin gm l0 6-nitrobenzimidazole nitrate .5% sol cc 80 Sodium hydroxide --gm 2O Ammonium thiosulphate gm 50 Polyvinylpyrrolidone gm 10 The specifioquantities of ingredients indicated in the above examples are not to be construed as limiting the range of quantities embraced by the invention. The useful ranges of these quantities may be expanded as set forth in'the appended claims What is claimed is:

1. A one step processing bath for exposed. silver halid photosensitive materials comprising developing elements including 1-pl1enyl-3-pyrazolidone and fixing agents in proportion to provide simultaneous complete development and fixing of the image and 400 to 1000 cc. of 12.5% r a solution sodium polyacrylate and 3 to grams of polyvinylpyrrolidone per liter of solution.

. 2. A one step processing 'bath for exposed silver halide photosensitive material comprising:

Sodium polyacrylate 12.5% solution cc 400 to 750 g 3. A one step processing bath for exposed silver halide photosensitive materials containing a quantity of sodium polyacrylate as thickening material and containing the 7 following ingredients:

Water to make 1 liter.. 1 'Metol gm 5 to 15 Sodium sulphite gm '40 to 70 Hydroquinone gm to 100' Potassium alum u grn 10 to Sodium hydroxide gm 2% 1040' 1 Sodium thiosulphate gn1 to Polyvinyl pyrrolidone cc 3 to 15 .5% solution of 6-nitrobenzimidazole cc 15 to 30 References (liter! by the Examiner I UNITED STATES PATENTS 2,543,181 2/51 Land 96-29 2,658,045 11/53 Schildknecht 96-114 2,834,676 5 /58 Stanley et a1. r 2,875,052 2/59 Weyde 96-114 X 2,901,350 8/59 Goldhammer. 2,948,614 8/60 Allen et al. 96-409 3,058,826 10/62 Meerkamperet al.

7 OTHER REFERENCES Keelanz Photographic Engineering, vol. 4, No. 3 {1953),pages157-161.

Keelan: Journal of Photographic Science, vol.' 5 (1957), pages 144145. 

1. A ONE STEP PROCESSING BATH FOR EXPOSED SILVER HALIDE PHOTOSENSITIVE MATERIALS COMPRISING DEVELOPING ELEMENTS INCLUDING 1-PHENYL-3-PYRAZOLIDONE AND FIXING AGENTS IN PROPORTION TO PROVIDE SIMULTANEOUS COMPETE DEVELOPEMENT AND FIXING OF THE IMAGE AND 400 TO 1000 CC. OF 12.5% SOLUTION SODIUM POLYACRYLATE AND 3 TO 15 GRAMS OF POLYVINYLPYRROLIDONE PER LITER OF SOLUTION. 